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  <title>预定义常量</title>

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</div><hr /><div id="array.constants" class="appendix">
 <h1>预定义常量</h1>

 <p class="simpara">
下列常量作为 PHP 核心的一部分总是可用的。
</p>
 <p class="para">
 <dl>

  
   <dt>

    <strong><code>CASE_LOWER</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
     <strong><code>CASE_LOWER</code></strong> 用在
     <span class="function"><a href="function.array-change-key-case.html" class="function">array_change_key_case()</a></span> 中将数组的键名转换成小写字母。这也是
     <span class="function"><a href="function.array-change-key-case.html" class="function">array_change_key_case()</a></span> 的默认值。
    </span>
   </dd>

  
  
   <dt>

    <strong><code>CASE_UPPER</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
     <strong><code>CASE_UPPER</code></strong> 用在
     <span class="function"><a href="function.array-change-key-case.html" class="function">array_change_key_case()</a></span> 中将数组的键名转换成大写字母。
    </span>
   </dd>

  
 </dl>

 </p>

 <p class="para"> 排序顺序标识：
 <dl>

  
   <dt>

    <strong><code>SORT_ASC</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
     <strong><code>SORT_ASC</code></strong> 用在 <span class="function"><a href="function.array-multisort.html" class="function">array_multisort()</a></span>
     函数中，使其升序排列。
    </span>
   </dd>

  
  
   <dt>

    <strong><code>SORT_DESC</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
     <strong><code>SORT_DESC</code></strong> 用在 <span class="function"><a href="function.array-multisort.html" class="function">array_multisort()</a></span>
     函数中，使其降序排列。
    </span>
   </dd>

  
 </dl>

 </p>

 <p class="para">
  排序类型标识：用于各种排序函数
 <dl>

  
   <dt>

    <strong><code>SORT_REGULAR</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
     <strong><code>SORT_REGULAR</code></strong> 用于对对象进行通常比较。
    </span>
   </dd>

  
  
   <dt>

    <strong><code>SORT_NUMERIC</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
     <strong><code>SORT_NUMERIC</code></strong> 用于对对象进行数值比较。
    </span>
   </dd>

  
  
   <dt>

    <strong><code>SORT_STRING</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
    <strong><code>SORT_STRING</code></strong> 用于对对象进行字符串比较。
    </span>
   </dd>

  
  
   <dt>

    <strong><code>SORT_LOCALE_STRING</code></strong>
    (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">
    <strong><code>SORT_LOCALE_STRING</code></strong> 基于当前区域来对对象进行字符串比较。PHP
    4.4.0 和 5.0.2 新加。
    </span>
   </dd>

  
 </dl>

 </p>
 <dl>

  
   <dt>

    <strong><code>COUNT_NORMAL</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>COUNT_RECURSIVE</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_OVERWRITE</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_SKIP</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_PREFIX_SAME</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_PREFIX_ALL</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_PREFIX_INVALID</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_PREFIX_IF_EXISTS</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_IF_EXISTS</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
  
   <dt>

    <strong><code>EXTR_REFS</code></strong>
     (<span class="type"><a href="language.types.integer.html" class="type integer">integer</a></span>)
   </dt>

   <dd>

    <span class="simpara">

    </span>
   </dd>

  
 </dl>

</div>
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